1. Field of The Invention
The present invention relates to an improved structure of the cold and hot water mixing valve of a balance valve, and especially to a structure for improving the sealing features of the fixing disk and the balance valve cover plate, and the balance valve cover plate and the lower wall of the mixing valve of the cold and hot water mixing valve.
2. Description of the Prior Art
U.S. Pat. No. 5,983,918 "Balancing Valve Assembly of a Cold and Hot Water Mixing Valve" is disclosed by the applicant of the present invention. In the prior art, a concave portion is installed on the lower wall of the mixing valve gate. A concave lower seat of a balance valve is installed with the hot water inlet. A sealing trench is installed on the concave portion along the water outlet preset on the lower wall and the peripheral of the lower seat of the balance valve. Besides, a balance valve cover plate symmetric to the shape of the concave portion of the gate body is further installed. The balance valve cover plate is also symmetric to the lower wall of the gate body. While a concave balance valve upper seat is installed below the cold and hot water inlet. Accordingly, the balance valve cover plate can be fixed within the concave portion of the gate body. Then a sealing is engaged in the trench of the lower wall of the gate so that the lower seat of the balance valve of the gate body and the upper seat of the balance valve of the cover plate are formed as a drain-preventing space. Thus, a balance valve body is fixed therewithin. Therefore, the components can be assembled easily and rapidly. The assembled structure is steady.
In the prior art, a sealing trench is installed on the water through holes and the periphery of the lower seat of the balance valve. A sealing ring with a shape symmetric to that of the sealing trench is embedded into the trench for water-sealing to the contact interface between the balance valve cover plate and the lower wall of the gate body. A further sealing trench is installed on the periphery of the water through hole on the upper surface of the balance valve improved structure of the cold and hot water mixing valve of a balance valve, and a matched sealing ring having a shape symmetric to that of the sealing trench is embedded thereinto for providing a water-sealing to the contact interface between the fixing disk and the balance valve cover plate. In this sealing structure, the sealing ring is located in the trench on one surface of the contact interface. By the part of the sealing ring protruded from the trench, it contacts with a respect flat surface. The flat surface applies a pressure to the protruded portion from the sealing ring so as to form a sealing feature by a contact interface. The sealing effect is determined by the positioning ability of the sealing ring, that is the compressing force of the flat surface applied to the sealing ring.
It is appreciated that in the practical application of a cold and hot water mixing valve, in some applications, water flow through the water through holes has a larger flow velocity and water pressure. For example, the high water pressure of a tall building or high pressure flush water, etc. Thus, the aforementioned prior art is installed with a balance valve in the cold and hot water mixing valve for preventing abnormal water pressure variation to cause the threat from using water in safety. For the sealing structure of the prior art, this high pressure water flow will destroy the sealing feature, even the sealing ring will displace so that one part of the sealing ring will move out of the respective position or out of a trench. This abnormal condition will cause the sealing ring to be clamped between the disk and the edge of the trench of the positioning trench so to deform or wear out completely and thus the sealing feature will loss completely. Besides, by enhancing the pressure between the contact interfaces to increase sealing effect, this will induce that the fixing disk and the movable disk within the valve body are compressed tightly. As a result, the water control valve can not be operated easily.